In the usage of modern computer systems and networks, the situation arises where systems having one proprietary protocol and data format are connected to systems having different data formats and protocols. Thus in order to provide for systems integration in different networks, it is necessary that there be provided a system or method whereby the data formats of a first system can be transferred to and utilized by the network of a differently oriented system.
For example, the Unisys A Series computer systems involve a Central Processing Unit and memory together with storage such as disk storage which operates under the control of a Master Control Program. These A Series systems use a particular format for the data files compatible with the A Series software which can be placed on CD-ROMs. Thus, the CD-ROMs which contain this A Series software contain an image of a formatted tape which can be utilized only by the A Series systems.
However, when it is desirable to integrate a first system such as the A Series systems for operation with other platforms such as an NT system, then problems arise in that the second system such as the NT system, utilizes formats which are not compatible with the software formats of the A Series system, which is the first system.
Presently, the software for a first system, such as an A Series system with software, is utilized by providing methods to burn CD disks from a Library Maintenance formatted tape. This method has the limitation in that it limits the type of files that are burned into CD-ROMs to those of the native A Series files.
Now, in order to provide for system integration where an A Series system is to be coupled to a NT system, which overall system would be designated as a Unisys ClearPath system, the desirability here would be to make and use a single CD-ROM disk which would carry both the A series software and at the same time carry the NT software.
Thus in this regard, a method is needed to couple the A Series files with their native attributes and also arrange them in a format capable of being stored on a particular media such as a CD-ROM which will also hold the readable software for the NT system.
The same system or method also provides the ability to package files of a proprietary system in such a way that allows the files to be transported across an open (non-proprietary) network without losing their original characteristics. When such files return to their native environment, their true data formats can be restored.
For example, the A Series systems have files with specialized attributes such as FILEKIND, CREATIONDATE, RELEASEID, etc. When these files are transferred to a PC running Windows NT, all those attributes will be lost. By packaging the files and their attributes into standard, simple text files, the now files then can be transported across any open system (e.g., UNIX, NT). Upon reaching their destinations (which are other A Series systems), the text files are converted back to their native forms with all the right attributes. This is ideal for maintaining A Series data formats in a heterogeneous networking environment.
A digital signature is calculated for every file or container of files, as it is being WRAPPED (packaged). This signature is calculated using the Disk File Header (DFH) and the data within the file, along with the Public/Private key pair. This will ensure that there is no intentional corruption of the Disk File Header (DFH) and the data as the file is shipped across a network. It will also provide the receiver of the file a certain measure of confidence as to the origin of the file. Additionally to the signature, there will be calculated a checksum for the entire contents of the file, including the Disk File Header.
When a file is wrapped with a request for digital signature, its Disk File Header will have a checksum, its entire file will also have another checksum, and a digital signature will be calculated for the entire contents of the newly wrapped file. The functionality of wrapping files with digital signature is available through the WFL syntax as well as through programmatic interface.
As a result, the Unisys A Series systems will provide a programmatic interface to its Master Control Program (MCP) which will provide a mechanism for "wrapping" containers with signature and for "Unwrapping" signed wrapped containers.
Wrapping is a term which is used to define the process of packaging an A Series file, along with its Disk File Header information and a checksum and optionally a digital signature, as a byte-stream data file, so that it can be transported across heterogeneous networks and non-A Series specific media, while still maintaining its native A Series attributes.
Unwrapping is a term used to define the process of taking a previously "wrapped file" and coupling it with the information from its original Disk File Header (DFH) in order to restore the original native A Series file, as it existed prior to being wrapped.
Thus, the problem of a software and file format which is oriented to one specialized system can now be transformed in order to provide a format that is utilizable not just for a first system, but also for a first and second system, whereby the second system would not ordinarily be compatible with the first system. Thus, it is desirable to allow files (created on a Unisys ClearPath HMP/NX system or A-Series system) to be transformed so they can travel across a completely different system (such as NT) without loss of the file's original native characteristics.
The presently described system and methods provide for taking one or more files in a first format such as used in Unisys A-Series systems and putting them into a single container file of a second generalized format for transport to an open network without losing the native attributes and for burning into a CD-ROM such that now this container file format is compatible for both NT and other systems in addition to A-Series systems.
The second file format container will provide a signature to be created for the entire file. This is so, since the checksum is not sufficient to ensure that a Disk File Header has not been intentionally corrupted, since the checksum algorithm is not protected, and could easily be reproduced. A signed, wrapped container file can be sent to another user through e-mail, through the Internet, or put into an industry-standard CD-ROM.
Thus, the packaged (wrapped) container file can be transported to an open network without loss of the native attributes and can be burned onto an industry-standard CD-ROM without loss of native attributes. In each case, a digital signature is generated to ensure the integrity of the packaged file.
CONTAINER: "A container", as used herein, involves a byte stream file, usually holding multiple files, together with a "directory" of the files that are stored. There is a considered distinction between a "wrapped file" and a "wrapped container". The wrapped container is a special file whose contents include one more wrapped files and a directory. A single wrapped file has no directory within itself.